\include{preambule}

\begin{document}
	\include{title_page}
	\section{Problem 2}
		The problem on our previous code version was on the set complement. The operator was not the good one. Indeed to complement a set \verb?not()? must be used.\\
		The code is then :
		\begin{verbatim}
			<Big_countries_with_no_Danube>
{
let $x := tokenize(doc('/db/mondial/mondial-europe.xml')
/mondial/river[name='Donau']/@country, "\s")

for $c in doc('/db/mondial/mondial-europe.xml')/mondial/country[population >= 30000000]
	where not($c/@car_code = $x) 
	order by $c/name ascending
return <country car_code="{$c/@car_code}">{$c/name}{$c/population}</country>
}
</Big_countries_with_no_Danube>
		\end{verbatim}
		
		The result of that query is :
		
		\begin{verbatim}
<Big_countries_with_no_Danube>
    <country car_code="F">
        <name>France</name>
        <population>58317450</population>
    </country>
    <country car_code="I">
        <name>Italy</name>
        <population>57460274</population>
    </country>
    <country car_code="PL">
        <name>Poland</name>
        <population>38642565</population>
    </country>
    <country car_code="R">
        <name>Russia</name>
        <population>148178487</population>
    </country>
    <country car_code="E">
        <name>Spain</name>
        <population>39181114</population>
    </country>
    <country car_code="TR">
        <name>Turkey</name>
        <population>62484478</population>
    </country>
    <country car_code="GB">
        <name>United Kingdom</name>
        <population>58489975</population>
    </country>
</Big_countries_with_no_Danube>
		\end{verbatim}
\end{document}